Python中is和==的区别

"""

is和 ==的区别

"""

a = 'abc'
b = 'abc'

print("都是字符串-a is b--", a is b)
print("都是字符串-a == b--", a == b)

c = 11
d = 11

print("都是数字-c is d--", c is d)
print("都是数字-c == d--", c == d)

e = [0, 1, 2]
f = [0, 1, 2]

print("都是列表-e is f--", e is f)
print("都是列表-e == f--", e == f)

g = h = [0, 1, 2]
print("都是列表-g is f--", g is h)
print("都是列表-g == f--", g == h)

i = (0, 1, 2)
j = (0, 1, 2)
print("都是元祖-i is j--", i is j)
print("都是元祖-i == j--", i == j)

k = {"name": "张三"}
m = {"name": "张三"}
print("都是字典-k is m--", k is m)
print("都是字典-k == m--", k == m)

print("a的id--", id(a))
print("b的id--", id(b))
print("c的id--", id(c))
print("d的id--", id(d))
print("e的id--", id(e))
print("f的id--", id(f))
print("g的id--", id(g))
print("h的id--", id(h))
print("i的id--", id(i))
print("j的id--", id(j))
print("k的id--", id(k))
print("m的id--", id(m))

输出结果:

总结：is是判断id是否相等，==是判断数据是否相等，如果两个变量的值是字符串，数字，元祖，那么is和==的结果无区别。如果是列表和字典，is是false，==是true，特例 g = h = [0, 1, 2]这样的列表，is也是true，因为指向同一空间地址